IMO, the only truly Germanic-balto-slavic people mix where the Bastanae
http://en.wikipedia.org/wiki/Bastarnae
Scholars hold divergent theories about the ethnicity of the Bastarnae. The mainstream view, following what appears to be the most authoritative view among ancient scholars, is that they were Germanic.[19][20] However others hold that they were mixed Celtic/Germanic,[21][22] or mixed Germanic/Sarmatian. A fringe theory is that they were Proto-Slavic.[8]
Lands where from Pomerania to the black sea of moldovia